Coupling and crosslinking a nucleic acid is a basic technique in the field of molecular biology. For example, coupling and crosslinking a nucleic acid is used in combination with hybridization in order to introduce a gene and detect a base sequence. Or, for example, in order to inhibit gene expression. Therefore, technologies for coupling and crosslinking a nucleic acid are extremely important not only for basic research in molecular biology but also for use in, for example, diagnosis and treatment in the field of medicine, or development and manufacture of therapeutic agents, diagnostic agents and the like, and development and manufacture of enzymes, microorganisms and the like in the field of industry and agriculture.
As the aforementioned technologies for coupling or crosslinking a nucleic acid, those in which photoreactions are used in the absence of enzymes have been gathering attention because the reactions have fewer restrictions in terms of time and spatial control, and may be performed under milder conditions than those used for common organic chemical reactions and the like.
Such technologies for photoreaction of nucleic acid include a photo coupling technology in which 5-cyanovinyldeoxyuridine is used (Patent Literature 1: Japanese Patent No. 3753938, Patent Literature 2: Japanese Patent No. 3753942), a photo crosslinking technology in which a modified nucleoside having a 3-vinylcarbazole structure at the base moiety is used (Patent Literature 3: Japanese Patent No. 4814904, Patent Literature 4: Japanese Patent No. 4940311).